Table of Contents
Advertisement
CDM-600L Satellite Modem
Front Panel Operation
CONFIG: RX: RX-IF
ACQUISITION SWEEP RANGE = +/- 10 kHz
RX FREQ=1200.0000MHz SPECTRUM INVERT=OFF
Edit the Acquisition Sweep Range of the demodulator. The value of the digit is changed
using the [↑] [↓] arrow keys. Press ENTER.
The value entered determines the amount of frequency uncertainty the demodulator will
sweep over in order to find and lock to an incoming carrier. When operating at low bit
rates, large values of sweep range (compared to the data rate) will cause excessively long
acquisition times. For example: selecting ± 32 kHz with a data rate of 2.4 kbps, BPSK,
will result in an average acquisition time of around 3 minutes.
Edit the Receive Frequency (RX FREQ) of the demodulator. Select the digit to be edited
using the [←] [→] arrow keys. The value of the digit is changed using the [↑] [↓] arrow
keys. Press ENTER. Note that the range is from 950 to 1950 MHz.
SPECTRUM INVERT should normally be in the OFF position. When in the ON position,
the receive spectrum is inverted (which is the same as reversing the direction of phase
rotation in the demodulator). Note that in BPSK mode, the demodulator will automatically
synchronize to either the normal time-ordering of bits FEC codeword pairs, or the inverted
ordering used by certain other manufacturers.
CONFIG: RX: DECODER
DECODER= VIT (NONE,VIT,SEQ,TCM,TPC,LDPC)
REED-SOLOMON = OFF (ON,OFF)
Select the parameter to edit using the [←] [→] arrow keys.
The Decoder options are shown in the parentheses. Select using the [↑] [↓] arrow keys,
then press ENTER. The choices are:
•
•
•
•
•
•
* This coding option is only shown when a Turbo codec is installed.
** This coding option is only shown when a TPC/LDPC codec is installed.
Viterbi
Sequential
Trellis Coded Modulation - 8-PSK Rate 2/3 only (FAST option)
TPC (Turbo) (Hardware option) *
None (uncoded)
LDPC (Hardware option). **
6–14
Revision 2
MN/CDM600L.IOM
Advertisement
Table of Contents
